1. Field of the Invention
The present invention relates to engine valves and more particularly pertains to a variable duration rotary valve which may be axially adjusted for varying an open duration of the valve.
2. Description of the Prior Art
The use of engine valves is known in the prior art. More specifically, engine valves heretofore devised and utilized for the purpose of varying a duration of the valve are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
For example, a rotary valve arrangement is illustrated in U.S. Pat. No. 4,517,938 which has a rotary valve member disposed within a housing and a series of circumferential dry-bearing, gas-sealing rings arranged to block leakage between adjacent passageways in the valve member.
Another patent of interest is U.S. Pat. No. 4,751,900 which teaches an adjustable segmented rotary twin port valve shaft useful for the introduction and exhaustion of gases of the internal combustion engine. The device includes an adjustable rotating valve shaft driven by the crank shaft, with the valve shaft having both intake and exhaust passages separated by annular sealing rings. The complete shaft assembly rotates in a lubricated bore, with the bore having access to openings to the combustion chambers of all cylinders of the engine. The rotating shaft rotates at one-fourth speed that of the crank shaft, thereby reducing wear and noise levels to a minimum, and providing full opening and closing of passages in shorter periods of time at proper sequence of valve timing, and eliminating all reciprocating parts which are found in conventional valve systems today.
Other known prior art engine valves include U.S. Pat. Nos.: 4,969,918; 3,522,797; 2,302,442; 2,156,749; 1,974,454; 1,923,666; 1,908,680; 1,724,458; 1,249,506; 1,213,027; and British Patent 25,291.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a variable duration rotary valve which may be axially adjusted for varying an open duration of the valve which includes a rotary valve having a substantially wedge shaped, contoured aperture allowing passage of a combustion mixture through both an intake port and engine port and into the combustion chamber of an engine, whereby an axial movement of the valve aligns various portions of the contoured aperture with the intake port to effect a controlled variance of the duration of time the valve permits flow through the ports.
In these respects, the variable duration rotary valve according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of varying an open duration of the valve.